cobra 29 no receive

[Trainwreck]

Got a cobra 29 with very little to no receive. If you tap the top of the case it receives fine till it fades out again, anybody got any idea where to start to fix this.....cause i cant seem to find where or why it is doing it thanks for the help and ideas on where to start

 

[Lil'Yeshua]

Cobra Service Bulletins ?
http://www.cbtricks.com/radios/cobra/service_bulletins/graphics/tsb_10025.pdf
http://www.dtbradio.com/tips.html

 

[sonoma]

Got a cobra 29 with very little to no receive. If you tap the top of the case it receives fine till it fades out again, anybody got any idea where to start to fix this.....cause i cant seem to find where or why it is doing it thanks for the help and ideas on where to start

have you tried touching up solder joints around the vco and crystals and the audio chip. sounds more like cold solder joint from tapping on the radio. have loosened the thumb screws from the brkt . do you have it in or out of the vehicle?
take a plastic tool and press around on the circuit board and see if you can find the spot that it is doing it at. then solder all the parts in that area.

 

[Trainwreck]

have you tried touching up solder joints around the vco and crystals and the audio chip. sounds more like cold solder joint from tapping on the radio. have loosened the thumb screws from the brkt . do you have it in or out of the vehicle?
take a plastic tool and press around on the circuit board and see if you can find the spot that it is doing it at. then solder all the parts in that area.

have tried to resolder.not in vehicle,and no thumb screws, had tried everything and cant seem to find the right spot.

 

[sonoma]

take a plastic tool and lightly push on the circuit board and see if you can find the area where it will cut in and out. check the legs of the 9 or 10 legged chip mounted to the side of the case also for cold solder joints.

do you have a magnifing glass you can look real close at the solder points also. a lot of times you can see where the solder is bad at the part.

 

[Trainwreck]

take a plastic tool and lightly push on the circuit board and see if you can find the area where it will cut in and out. check the legs of the 9 or 10 legged chip mounted to the side of the case also for cold solder joints.

do you have a magnifing glass you can look real close at the solder points also. a lot of times you can see where the solder is bad at the part.

Ok i have tried that several times and nothing.....i am at a stand still. I have checked the components in the the receive circuit and all seem fine. Am i missing something or should i just junk the radio

 

[sonoma]

since you said it fades out and you can tap on it and it comes back I still think it has a bad solder joint that you are not finding.

 

[Duppy Conquerer]

Little or no receive

First things first, look at the simple and more practical side of thing s before you jump to the more complex...more than likely your problem is either at the microphone end by the socket, or at the antenna connnection, either by the coax connector where it connects to the radio. In either case, you need to do a wiggle or tap test at either points and see ...i feel pretty confident thats where you problem resides. Good luck, and let us know how you make out.

 

[Duppy Conquerer]

Little or no receive

First things first, look at the simple and more practical side of thing s before you jump to the more complex...more than likely your problem is either at the microphone end by the socket, or at the antenna connnection, either by the coax connector where it connects to the radio. In either case, you need to do a wiggle or tap test at either points and see ...i feel pretty confident thats where you problem resides. Good luck, and let us know how you make out.op:

 

[Robb]

First things first, look at the simple and more practical side of thing s before you jump to the more complex...more than likely your problem is either at the microphone end by the socket, or at the antenna connnection, either by the coax connector where it connects to the radio. In either case, you need to do a wiggle or tap test at either points and see ...i feel pretty confident thats where you problem resides. Good luck, and let us know how you make out.op:

You left out the speaker connection and the external speaker jack . . .

 

[Duppy Conquerer]

Robb, good point, however, in keeping it kiss, and being practical..its most likely that the problem evolves from an area that involves a lot of movements or changes by the operator of the radio. And yes, the area you pointed out falls within such realm of practical simplicity, providing that prior to the problem exhibiting itself, that, the external speaker jack port was heavyly or improperly used, but being that there was no evidence or suggestion to support such thought, it was omitted. Has i suggested previously, it would be most likely in the area of the mic connection or antenna connection by the radio. Also, a cold solder joint is a possibility, but its always better to start with the simplest and most probable before delving into the more complex arena. Its very good to see the outpour of support here. Thumbs ups to all, and have a Blessed evening, Robb.

 

[midnight special]

guys, i had the same problem with a 29 once, it was the screws that hold the board to the chassis. they were loose tightened them up radio came back to life. so i would check the screws,..........

 

[bigwheel82]

any jumpers being used? I've had this same effect and it was due to badly soldered jumpers to my power meter.

 

[959]

replace your final

 

[959]

I have the same problem with a uniden pc 78 elite but I cant find the problem either they are both the same radio with a different name same board